Tooth



Dec. 15, 1931. I

R. E. HALL TOOTH Filed July 23, 19 28 Patented Dec. 15, 1931 RUPERT E. HALL, OF CHICAGO, ILLINOIS TOOTH Application filed July 23,

My invention relates to improvement in the occlusal, or masticating, portions of artificial teeth for use in'full denture restoration and partial denture and crown and bridge work where the cusps of remaining natural teeth which the artificial teeth are to oppose, are worn away presenting flat, or substantially flat, occlusal portions, the improvement relating more especially to the posterior or molar and bicuspid teeth.

In accordance with the practice now prevailing the artificial teeth are patterned after the natural teeth thereby presenting cusps which interlock in the masticating operation and cause the denture bases to become dislodged, the supporting tissues becoming broken down, oftentimes in a comparatively short-time, with the result that the denture bases change their relative positions to each 29 other and the opposing teeth cease to occupy the proper positions relative to each other.

My object is -to. overc ome the difliculty above set forth to the end that the denture bases will not become dislodged, the tissues modified and the opposing teeth changed in their relation to each other.

Generally stated, this I accomplish by so forming the teeth that they will be devoid of cusps such as is the case in natural teeth, and providing the occlusal portions of the teeth of such form that, while the necessary and desired cutting surfaces are provided for proper mastication or food, no portions thereof occupy such positions relative to teeth with which they occlude tha they interlock, as in the case of cusp-teeth.

Referring to the accompanying drawings in which I have shown my invention as embodied in a pair of full denture plates,

Figure 1 is a side view of plates made with such teeth in occluded or opposing position when positioned for use in the mouth of the patient.

Figure 2 is'a bottom plan view of the posterior teeth at one side of the upper plate of Fig. 1. V Y

Figure 3 is a plan view of the posterior teeth at one side of the lower plate and opposing the teeth shown in- Fig. 2. v 1

Figure 4 is a sectional view taken at the 1928. Serial No. 294,632.

line 4 on Fig. 2 and viewed in the direction of the arrow.

Figure5 is a plan view of a modification of one of the bicuspids.

Figure 6 is a plan view of a modification 56 of one of the molars; and V Figure 7, a plan view of another modification of a molar.

In the plates illustrated the anterior teeth are of the common form the posterior teeth 60 only thereof, viz., the bicuspids and molars, being formed in accordance with my invention.

As shown the occlusal portions of the bicuspids, represented at 7 and of the molars, represented at 8, are substantially flat, these portions. being recessed, or cupped, as represented at 9, to provide at their marginal edges the cutting edges 10 for mastication, which are preferably, and as shown, continuous edges.

The bicuspids and molars are preferably single and double cupped. respectively, as shown in Figs. 1 to 4, inclusive, but if .de-

sired the second bicuspids and molars may be formed with two and four cups, respectively, as represented in Figs. 5 and 6, or the molars may be. formed with single cups, as represented in Fig. 7.

In the use of the teeth for mastication the cupped teeth move relative to each other crosswise of their substantially vertical axes in a substantially flat plane, as distinguished from the undulatory movement of one setof teeth relative to the other as in the case of natural or artificial teeth of the same shape as natural teeth due to their interlocking cusp formation, and thus dislodgment of the denture bases is avoided. Furthermore, the margins 10 of the orifices of the cups 9- cut and triturate food in a more eflicient manner and with the exert-ion of less force than in the case of cusp-teeth.

The invention is also applicable to arti- 95 ficial teeth which oppose natural teeth where the occlusal portions of the latter are worn flat, orsubstantially fiat, so that the relative movement of the teeth in mastication is in a substantially flat plane and without the 1 objectionable interlock between opposed teeth and incident to cusp-teeth.

What I claim as new, and desire to secure by Letters Patent, is:

1. An artificial tooth having its occlusal surface located in a single plane at right angles to the vertical axis of the tooth and formed with a cavity, the latter reducing the occlusal surface to a cutting edge lying substantially at the periphery of said occlusal surface.

2. An artificial tooth having its occlusal surface lying in a single plane at right angles to the vertical axis of the tooth and formed with a cavity, the latter reducing the occlusal surface to a continuous cutting edge lying substantially at the periphery of said occlusal surface and defined by the outline of said cavity.

3. An artificial tooth having its occlusal surface lying in a single plane at right angles to the vertical axis of the tooth and formed with a plurality of cavities, the latter reducing the occlusal surface to a cutting edge defined by the outlines of said cavities.

4. 'In combination coacting upper and lowerdentures each having its occlusal surface formed with a cutting edge, said occlusal surface lying in a single plane at right angles to the vertical axis of the tooth whereby when said surfacesare brought together they may be longitudinally and laterally actuated in the occlusal plane without 'cuspal interference.

5. In combination coacting upper and low er dentures each having its occlusal surface lying in a single plane at right angles to the vertical axis of the tooth and formed with a cavity, the latter reducing the occlusal surface to a cutting edge whereby whensaid surfaces are brought together they may be longitudinally and laterally actuated in the occlusal plane without cuspal interference.

RUPERT E. HALL. 

